CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Total Stockholders’ Equity	Preferred Stock	Common Stock	Additional Paid-in Capital	Cumulative Distributions in Excess of Net Income	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Balance (in shares) at Dec. 31, 2016			5,750,000	65,285,614
Balance at Dec. 31, 2016	$ 1,015,609	$ 1,015,574	$ 58	$ 653	$ 1,208,862	$ (192,201)	$ (1,798)	$ 35
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	54,396	54,438				54,438		(42)
Other comprehensive income	6,034	6,034					6,034
Change in noncontrolling interests	2,733							2,733
Amortization of stock-based compensation	8,768	8,768			8,768
Common stock issuance, net (in shares)				110,546,599
Common stock issuance, net	2,371,985	2,371,985		$ 1,105	2,370,880
Preferred dividends	(7,682)	(7,682)				(7,682)
Common dividends	(80,014)	(80,014)				(80,014)
Balance (in shares) at Sep. 30, 2017			5,750,000	175,832,213
Balance at Sep. 30, 2017	3,371,829	3,369,103	$ 58	$ 1,758	3,588,510	(225,459)	4,236	2,726
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASU 2017-12 adoption	0	0				(795)	795
Balance (in shares) at Dec. 31, 2017			5,750,000	178,255,843
Balance at Dec. 31, 2017	3,437,249	3,432,807	$ 58	$ 1,783	3,636,913	(217,236)	11,289	4,442
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	298,498	298,476				298,476		22
Other comprehensive income	14,273	14,273					14,273
Distributions to noncontrolling interests	(107)							(107)
Amortization of stock-based compensation	7,357	7,357			7,357
Preferred stock redemption			(5,750,000)
Preferred stock redemption	(143,750)	(143,750)	$ (58)		(138,191)	(5,501)
Common stock issuance, net (in shares)				29,132
Common stock issuance, net	(202)	(202)		$ 0	(202)
Preferred dividends	(4,267)	(4,267)				(4,267)
Common dividends	(241,793)	(241,793)				(241,793)
Balance (in shares) at Sep. 30, 2018			0	178,284,975
Balance at Sep. 30, 2018	$ 3,367,258	$ 3,362,901	$ 0	$ 1,783	$ 3,505,877	$ (171,116)	$ 26,357	$ 4,357